Holley 4150 Rebuild Question

I'm working on a 600 Holley and its my first time going through a rebuild. Everything seemed to go smoothly except for the leftover part that I have. I can't remember where I removed these pieces from and I've went through the carb several times trying to find it. The picture is below. Does anyone have any idea where this goes? Thanks in advance for the help.

From my recollection it all came out together from the same spot. I apologize for the blurry picture. The camera I'm using isn't very good. From left to right there is a check ball, a spring, a nipple type item with no hole, and a plug type item with slots for air or fuel (not sure).